Arguably PH-DDA crashed because it was mishandled; the aircraft was flown too slowly and once below Vmca control was lost. The failure of the No 1 engine to remain feathered caused significant drag which in turn the crew were unable to reduce. Easier in an armchair, but far more survivable to ‘arrive’ in a semi-controlled fashion with the wings level than to lose control and stall/spin.
The cycling of the feathering system is well documented for the DC3; press the Feathering button, watch the prop feather, pull the button out if you see the prop start to unfeather! The consequences of not feathering the prop in a twin are enormous.